Grease manufacture



Jan. 7, 1964 H. v. REEs ETAI. 3,117,085

GREASE MANUFACTURE Original Filed Dec. 24, 1955 thereto, there may be employed a centrifugal separator between it and the cooler 23, through which air is blown from the bottom to assist in getting rid of steam.

The product in hopper 27 will be a grease when the solid particles are of a material that has a gelling action on the lubricating oil. However, when the solid particles are of a material which has little or no gelling action on the lubricating oil a quantity of soap should be introduced into the dispersion to supplement the solid particles in their thickening or gellincr action. Soap may be injected at any place in the system between the mixer ll and the outlet We have shown by way of illustration the introduction ot soap from a supply conduit 3S into the discharge tube E9, alternatively through a valvecontrolled conduit 37 upstream of nozzle 2i or a valvecontrolled conduit 39 downstream of the nozzle.

When the soap is injected upstream of the nozzle it is intimately and thoroughly mixed with the vaporous dispersion as it passes through nozzle 21 at high velocity. A less thorough, but still effective, mixing can be expected when the soap enters conduit l@ downstream of the nozzle, or when no nozzle is used. It is apparent that soap also may be added in the hopper 27 Where it is thoroughly mixed with the oil dispersion by the stirrer 29.

The following specific examples illustrate how the form of the invention described in connection with FIG- URE l can be applied to prepare specilic grease compositions.

Example I A slurry is made up consisting 82% by Weight of a mineral oil having a viscosity of 4l SUS (Saybolt Universal seconds) at 100 F. and a boiling range of 534- 700 F., together with 18% weight of graphite fragments averaging about 1/s inch in diameter. 2200 lbs/hr. of this slurry are pumped into 1/2 heating tubing 15, 600 feet long wherein it is heated to a temperature of 750 F. and vaporizes, the resulting dispersion reaching a velocity in excess of 500 feet per second. Nozzle 21. is omitted. Thereafter the dispersion enters the cooler 23, and the resulting dispersion of ultra line carbon particles in oil is discharged into the hopper 27 as a highly liquid hot grease which is withdrawn through outlet 33.

Example ll A slurry consisting 18% of graphite fragments and 82% of mineral oil is passed through the system of FG- URE 1 as described in Example l. A hot sodium stearate soap at a temperature of 250 F. is introduced through conduit 37 in a steady stream owing in such volume as to provide a mixture containing about of soap. The resulting grease leaving the outlet 33 has a thicker consistency than that described in Example I and sets up t0 form a relatively thick and viscous grease when cooled.

Example III A slurry composed about 40% by weight of silica gel particles (containing 60% water by weight) 2-4 mesh in size (US. Standard), and. about 60% of a naphthene base lubricating oil having a viscosity of about 310 SUS at l00 F. and a boiling range of 6l9-S78 F. is made up in the slurry mixer 11. 800 lbs./ hr. of this slurry are pumped through the conduit i3, and a 1/2 heater tube 400-feet long where it is heated to 800 F. and the water of the silica gel and most of the oil content of the slurry are vaporized. The resulting dispersion attains a velocity in excess of 1000 feet per second in passing through nozzle 2l. The oil is then condensed in cooler 23 by cooling the vapors to a temperature of 400 F. while the water vapor from the silica gel remains in the vaporous condition. The resulting liquid grease containing ultra line particles of silica is then passed into the receiver 27 wherein the grease is agitated to cause entrapped water vapor to separate and pass out through conduit 31.

4 Example IV The same mixture of silica` gel and lubricating oil is made up and passed through the system of FIGURE l as described in Example lll. The gelling action of the ultra tine silica however, is supplemented by bleeding in hot liquid sodium stearato soap at a temperature of 350 l?. through conduit 37 in a volume to provide 5% of soap by weight in the linal mixture.

Referring to FEGURE 2 of the drawings, a second em-l bodiment of the invention involves forming in a mixer 41 a fluid compound of the solid grease component from supply conduit l2 with a liquid from conduit 44, suitable additives also being introduced through conduit 82 if desired. Preferably the slurry employs as the liquid component water or another easily Vaporizable liquid other than the oil of the linal grease. The slurry is then pumped through a conduit d3 into a long heating tube 45 which may be coiled or otherwise arranged within a gas or oil tired heater 47. The water or other slurry liquid is vaporized by heating it to a temperature well above its boiling point, and a dispersion of solid particles in the resultng vapor is formed which flows continuously at high velocity in turbulent ilow through the latter portion of tubing 45.

rhe resulting dispersion then passes by a conduit 49 through a nozzle Si of the type described in connection with FIGURE l, and then into a separator 53 wherein the vapor is separated from the solid particles, the vapor passing ott the top through a conduit 55 and the dry solid particles passing continuously out the bottom through an outlet 57. Nozzle Si is not essential and may be omitted it esired. Separator 53 may have any desired conventional construction such as that of a cyclone separator wherein the vapor is separated from the solid particles by centrifugal action, with or without the addition of air blowing up through the separator from the bottom to dry the solid.

Alter the solid particles leave separator 53 a grease is compounded by mixing a lubricating oil with the particles and, where necessary, by also adding soap to effect gellalion. Lubricating oil is supplied by a conduit 59 to heater '5i' and thence by a conduit o3 into the outlet conduit 57 for mixture with the solid particles. The resulting suspension ows by conduit into a mixer 67 of any suitable conventional construction, such as Gte having a motor-driven spiral mixing screw 69.

When the solid particles are of a material such as silicar which has a gelling action on lubricating oil i-t frequently is not necessary to add a soap. However, when a soap 1s necessary to elect gellation or to supplement the action of the solid particles, Iit is supplied by a conduit 71 to a heater 61 and thence by a conduit 73 into the mixer 67 wherein it is intimately combined with the oil and solid particles.

The economy of operation is improved by using steam from Ithe top of the separator `53 as the heating medium for the heater dl. Process steam also is passed from heater 6d through a jacket 75 surrounding mixer 67 for heating the grease during compounding. This process steam may be supplemented by the addition out auxiliary steam from conduits 77 and 79;-

.Some solids such as silica can only be wet with great dilhculty by the oil employed for making a grease. This. dimculty can be alleviated by incorporating a small quan-- tity of oil, such as =1 to 5%, in the liquid component of 'the slurry in mixer d1, vaporizing the oil with the slurry' liquid, and then con-trolling the temperature in separator 53 by suitable cooling luid so that only the oil oondenses uniformly on the individual tine solid particles. Another way is yto introduce .the oil into line 49 either before or after the nozzle Si and allow it to condense on the surfaces of the particles in 53. The resulting oil-wet particles are easily compounded with lubricating oil to form the grease. Other suitable materials for improving oil wettability are alkali and alkaline earth metal petroleum` sulfonates such as sodium and potassium petroleum sulfonates, these ma;erials also acting as dispersing agents to improve the suspension of solid particles in slurry liquid. Still others are acids and naphthenates.

Wettability of the solid particles can also be improved by mixing in the slurry feed a small quant-ity say up to 2% by weight, of iron or lead salts such as the chloride or nitrate and subsequently bleeding in hydrogen sulfide through a condr't Si or in the separator 53 lto form the sulfide which conditions the particles for oil Wettability.

he following examples will illustrate how the method described in connection with FIGURE 2 is carried out to produce specific grease compositions.

Example V Fragments of graphite about 1A inch in diameter are mixed with water in the mixer il to form a slurry containing 50% by weight of graphite which is then passed at the rate of 700 lbs/hr. through fthe heated tubing 45 for disintegrating the graphite. A velocity in excess of 1700 vfeet per second is attained by passage through tubing 45. in the separator 53 the steam is separated and passes oft through conduit 5S leaving dry hot finely divided carbon particles in the bottom or" the separator. A stream of a parafnic lubricating oil having a viscosity of about 300 SUS at 210 F. is .then passed through the heater 6l wierein it is heated to a temperature of 220 F. and enters the conduit 65 for mixture with the carbon particles leaving separator S3. The proportions are such as to produce a grease containing 25% by weight of carbon and 70% by weight of mineral oil. The resulting crude mixture of carbon and oil is delivered to mixer 67' while a stream of hot aluminum stcarate soap at 350 F. is simultaneously supplied from conduit 73 in sufiioient volume to provide 5% by weight oi soap in the iinal grease. Alfter thoroughly in the mixer 67 at a temperature of 350 l?. the linished liquid grease is discharged through outlet Example VI 23.69 parts of silica gel particles 2 4 mesh in diameter are mixed thoroughly in the mixer `4l with 76.31 parts olf water by weight so that the major portion of 'the silica gel forms a liquid gel with the water. The resulting fluid is passed at a rate of 1109 pounds per hour through the 1/2 inch tubular heating coils 45 wherein the water is hea-ted to 754 F. and vaporizes to form a dispersion iiowing at a velocity in excess of 2000 feet per second. After passing 4into separator 53 the steam is removed through conduit 55 and finely-divided spherical silica particles leave through outlet 5., having been reduced in sue to between .005 and 7 microns diameter. Hot mineral oil of about SUS` viscosity at 100 F. is then supplied through conduit e3 in volume such as to provide a final grease consisting 85% of mineral oil and 15%l of silica. by weight. rlhis mixture is then passed into the mixer o7 where an intimate dispersion is accomplished at a tempera-ture ot 250 F., after which liquid grease is discharged through outlet Example VII Silica as described in Example Vl is mixed with oil from conduit in proportions `to provide about by weight of silica and 80% by weight of lubricating eil in the had product. This mixture is then passed into mixer 67 which simultaneously is supplied with a sodium stearate soap from conduit 73 in sutlioien-t volume to provide 5% by weight of soap in the final grease.. After intimate mixing at a temperature of 300 the resulting liquid grease is dischm'ged lthrough outlet 84.

The principles of the invention have been illustrated above in connection with specific grease components. It is apparent, however, that they also apply when a wide variety md range of other components are employed. For example, solid particles olf many other gelling agents may be used, such as alumina, magnesia; calcium or maglnesiusn hydroxides; ferrous or ferric oxides and hydro-xides; vanadium oxide; silicates of magnesium, calcium, and aluminum; calcium sulfate, calcium carbonate, calcium phosphate, clay, and various forms of carbon such as carbon blacks. Such gelling agents may be employed in amounts between 1 and 2.5% of the final grease by weight, the `amount in any specific case depending upon the characteristics olf the particular gelling agent employed, Ithe grease consistency desired, and the quantity of soap used in conjunction therewith.

Extremely tine sub-division of the particles is necessary, and it is advantageous that they be ii-ne enough so that one gram has a ysurface area of 200 to 75-0 square meters as determined by adsorption of a mono-layer of nitrogen.

All solid materials do not necessarily have a gelling action on lubricating oil. Substances which do'not, however, yoften are used in conjunction with gelling agen-ts to impart specific properties to the grease. Among such additives are asbestos, mica, and talc, all of which may be incorporated in a grease by following the present invention. Others are antimony sullide; metal powders such as aluminum, lead, zinc, and copper; borax, barium sulfate, tricresyl phosphate, and sodium metaphosphate. Such additives may be introduced into the initial mixture through conduits 34 and S2 or at any other selected point.

The oil phase of a grease also can be varied widely, as is well known in the art. In general the oil phase can be composed of lubricating oil fractions of petroleum, which are a mixture of naphthenic, aliphatic, and aromatic hydrocarbons. When a natural mineral base lubricating oil is employed it may have a viscosity between 35 SUS at F. and 1,000 SUS at 210 F., depending upon the characteristics of the desired iinal grease product. Synthetic lubricants, such as the water soluble monoalkyl ethers of oxy-ethylene-oxy-l,2-propylene copolymers, may also be employed. One such synthetic lubricant sold by Carbide and Carbon Chemicals Corporation under the trademark Ucon fluid has viscosities between 100l and 660 SUS at 100 F.

The types of soap used in greases are well known in the art and may be employed in the method of the present invention to produce a grease of the desired inal characteristics. Metal soaps of aliphatic dicarboxylic fatty acids and hydroxy acids having more than 11 carbon atoms are generally employed, for example, salts of oleic, palmitic, myristic, arachidic, stearic, hydroxy stearic, and behenic acids. Other acids are sulfonic, rosin and naphthenic. Typical metal radicals in soaps are aluminum, lead and lithium, for example, as aluminum stearato, lead 12-hydroxy stearate, or lithium 12-hydroxy stearato. Other metallic radicals include one or more of copper, cobalt, nickel, cadmium, mercury, strontium, Zinc, Sodium, and

non.

A soap may also be formed in situ by incorporating a soap-forming base such as aluminum hydroxide in the original slurry or gel in mixer l1 or 4l, and then later adding a high molecular weight acid such as stearic to the mix after the latter has left the heating coils.

This application is a division of our application Ser. No. 400,266, led December 24, 1953, now Patent 2,948,679, issued August 9, 1960.

Obviously many modifications and variations of the invention as hereinbefore set forth may be made without departing from the spirit and scope thereof, and therefore only such limitations should be imposed as are indicated in the appended claims.

We claim:

1. In a continuous method for forming a grease, mixing relatively coarse solid particles of a gelling agent comprising at least one substance selected from the group consisting of silica, alumina, magnesia, calcium hydroxide, magnesium hydroxide, iron oxide and hydroxide, vanadium oxide; silicates of magnesium, calcium, and aluminum; calcium sulfate, calcium carbonate, and calcium phosphate; clay, and carbon with water to form a flowable mixture; passing said mixture into the initial portion of a long tubular zone; heating said mixture to above the boiling point of said water thereby forming in said tubular zone a dispersion of particles of said solid in steam; passing said dispersion through the latter portion of said tubular zone at high velocity in turbulent flow such that said solid is converted to fine particles of a size reduced greatly below the original size of said particles; separating said steam from said tine particles, leaving said particles in a hot and anhydrous condition; compounding said hot and anhydrous tine particles with lubricating oil; compounding soap with said ne particles and lubricating oil; and passing the separated steam in heat exchange relationship with said soap prior to compounding said soap, to heat the latter.

2. In a continuous method for forming a grease, mixing relatively coarse solid particles of a gelling agent comprising at least one substance selected from the group consisting of silica, alumina, magnesia, calcium hydroxide, magnesium hydroxide, iron oxide and hydroxide, vanadium oxide; silicates of magnesium, calcium, and aluminum; calcium sulfate, calcium carbonate, and calcium phosphate; clay, and carbon with Water to form a Howable mixture; passing said lmixture into the initial portion of a long tubular zone; heating said mixture to above the boiling point of said water thereby forming in said tubular zone a dispersion of particles of said solid in steam; passing said dispersion through the latter portion of said tubular zone at high velocity in turbulent tlow such that said solid is converted to tine particles of a size reduced greatly below the original size of said particles; separating said `steam from said tine particles, leaving said particles in a hot and anhydrous condition; compounding said hot and anhydrous ne particles with lubricating oil; and passing the separated steam in heat exchange relationship with said lubricating oil prior to compounding said oil, to heat the latter.

3. In a continuous method for forming a grease, mixing relatively coarse solid particles of a gelling agent comprising at least one substance selected from the group consisting of silica, alumina, magnesia, calcium hydroxide, magnesium hydroxide, iron oxide and hydroxide, vanadium oxide; silicates of magnesium, calcium, and aluminum; calcium sulfate, calcium carbonate, and calcium phosphate; clay, and carbon with water to form a ilowable mixture; passing said mixture into the initial portion of a long tubular zone; heating said mixture to above the boiling point of said Water thereby forming in said tubular zone a dispersion of particles or" said solid in steam; passing said dispersion through the latter portion of said tubular Zone at high velocity in turbulent ow such that said solid is converted to tine particles of a size reduced greatly below the original size of said particles; separating said steam from said tine particles, leaving said particles in a hot and anhydrous condition; compounding said hot and anhydrous fine particles with lubricating oil; and passing the separated steam in heat exchange relationship with said line particles and lubricating oil during compounding thereof.

4. A grease lmaking apparatus comprising iirst means for forming a tlowable mixture of a solid grease component in a liquid; second means providing an elongated tubular heating zone connected to said first means for vaporizing said liquid and producing particles of said solid grease component of small size; means for heating said mixture as it Vflows through said heating zone; a separator for separating vapor from said particles; a mechanical grease mixer connected to said separator for receiving said particles; means for supplying oil to said particles after leaving said separator for compounding therewith in said mixer; and means for passing the separated vapor in indirect heat exchange relationship with said mechanical grease mixer.

5. A grease making apparatus in accordance with claim 4, also comprising means for passing soap into said mixer for compounding with said oil and particles.

6. A grease making apparatus in accordance with claim 5, also comprising means for passing separated vapor into heat exchange relationship with said soap before said soap enters said mixer.

7. A grease making apparatus in accordance with claim 4, also comprising means for passing separated vapor in heat exchange relationship with said oil before said oil enters said mixer.

References Cited in the tile of this patent UNiTED STATES PATENTS 2,260,625 Kistler Oct. 28, 1941 2,554,222 Stross May 22, 1951 2,573,650 Peterson Oct. 30, 1951 2,583,603 Sirianni et al Jan. 29, 1952 2,625,508 Stross Ian` 13, 1953 2,735,787 Eastman et al Feb. 21, 1956 2,830,769 Work Apr. l5, 1958 2,856,268 Young Oct. 14, 1958 2,864,560 Carkeek etal Dec. 16, 1958 

1. IN A CONTINUOUS METHOD FOR FORMING A GREASE, MIXING RELATIVELY COARSE SOLID PARTICLES OF A GELLING AGENT COMPRISING AT LEAST ONE SUBSTANCE SELECTED FROM THE GROUP CONSISTING OF SILICA, ALUMINA, MAGNESIA, CALCIUM HYDROXIDE, MAGNESIUM HYDROXIDE, IRON OXIDE AND HYDROXIDE, VANADIUM OXIDE; SILICATES OF MAGNESIUM, CLACIUM, AND ALUMINUM; CALCIUM SULFATE, CALCIUM CARBONATE, AND CALCIUM PHOSPHATE; CLAY, AND CARBON WITH WATER TO FORM A FLOWABLE MIXTURE; PASSING SAID MIXTURE INTO THE INITIAL PORTION OF A LONG TUBULAR ZONE; HEATING SAID MIXTURE TO ABOVE THE BOILING POINT OF SAID WATER THEREBY FORMING IN SAID TUBULAR ZONE A DISPERSION OF PARTICLES OF SAID SOLID IN STEAM; PASSING SAID DISPERSION THROUGH THE LATTER PORTION OF SAID TUBULAR ZONE AT HIGH VELOCITY IN TURBULENT FLOW SUCH THAT 